The present invention relates to a control apparatus for a three-dimensional laser working machine. More specifically, this invention relates to a control apparatus for a three-dimensional laser working machine having a head structure that a working point does not change when a rotational axis and an attitude axis are rotated, and having a unit which teaches a tip position and a directional attitude of a nozzle.
As a three-dimensional laser working machine for working a sculptured surface, a three-dimensional laser working machine, which has a rotational axis (xcex1 axis) rotatable around a center axis of a Z axis (vertical axis) and an attitude axis (xcex2 axis) rotatable around an axis slanted with respect to the Z axis and has a head structure that when the rotational axis and the attitude axis are rotated, a working point does not change, is known (see Japanese Patent Application Laid-Open No. 1-162592 (1989)).
FIG. 6 schematically shows the working head having the rotational axis (xcex1 axis) and the attitude axis (xcex2 axis) In FIG. 6, the working head is shown by a reference numeral 50, and the working head 50 has a rotational axis 52, which is rotatable around a center axis of a Z axis by a bearing member 51, at the tip of a Z axis member 60, and an attitude axis 54, which is attached to the tip of the rotational axis 52 by a bearing member 53 and is rotatable around an axis slanted with respect to the Z axis, and a laser nozzle 61 is attached to the tip of the attitude axis 54. The working point is shown by a reference symbol N.
In the three-dimensional laser working of a sculptured surface, in order to maintain an optical axis of a laser emitted to a working surface in a normal direction with respect to the working surface, the laser nozzle is required to be always in an attitude which is orthogonal to the working surface, and teaching which fulfills this requirement is made prior to actual working.
There will be explained below an attitude change of the working head at the time of teaching an attitude change corner section with reference to FIG. 7. In FIG. 7, P1, P2 and P3 show teaching points of a workpiece W. The teaching point P1 is a teaching point on a horizontal surface, the teaching point P2 is a teaching point on a 45 degrees slanted surface of the workpiece W, and the teaching point P3 is a teaching point on an upright surface of the workpiece W. The laser nozzle 61 faces just downward at the teaching point P1, and is slanted 45 degrees at the teaching point P2, and faces the horizontal direction at the teaching point P3.
In order to bring the workpiece W into a state orthogonal to the teaching points P1, P2 and P3, it is necessary to change rotating angles of the rotational axis 52 and the attitude axis 54. For this reason, conventionally in the teaching operation on the attitude change corner section, an operator rotates the rotational axis 52 and the attitude axis 54 every time of the teaching, and brings the laser nozzle 61 into the orthogonal state with respect to the working surface and makes the teaching.
There will be explained below a procedure of the conventional teaching operation of the attitude change corner section with reference to FIG. 8. Firstly, various setting of a teaching box is carried out, and the teaching operation for teaching working points is brought into a startable state by using a working machine (step S100).
Next, an instruction such as shutter opening of an auxiliary function code which is the initial setting in the working program is given, and the working axis is moved to a teaching point by pushing down a working axis feed key which is positioned in the teaching box or by using a handle or a joy stick and the teaching is made so that respective teaching points of the working program are created (step S101). When the teaching points are created, in the conventional teaching operation on the attitude change corner section, for example in the case of the teaching from the teaching point P1 on the horizontal surface to the teaching point P2 on the 45 degrees slanted surface, the working head 50 is moved so that a tip coordinate meets the teaching point P2 on the 45 degrees slanted surface (step S102).
Next, the attitude axis 52 and the rotational axis 54 are moved independently by an operator so that the orthogonal state can be obtained (steps S103 and S104), and this operation is repeated until the orthogonal state is obtained (step S105).
After the orthogonal state is obtained, the tip coordinate is checked for displacement (step S106).
When displacement occurs, the sequence returns to the step S102 so that the tip coordinate is moved. After the tip coordinate is moved, in order to obtain the orthogonal state again, the attitude axis 52 and the rotational axis 54 are rotated. Namely, the steps S102 through S106 are repeated. Similarly, at the time of teaching from the teaching point P2 on the 45 degrees slanted surface to the teaching point P3 on the upright surface, the steps S102 through S106 are repeated.
When the program creation by the teaching operation of the attitude change corner section is completed, thereafter the working axis is moved to a teaching point by pushing down the Working axis feed key of the teaching box, or using the handle or the joy stick and the teaching is made so that the respective teaching points of the working program are created (step S107). However, if the teaching operation of the attitude change corner section is to be performed, then the steps S102 through S106 are executed. Finally, instructions such as shutter closing and program end of the auxiliary function code are given so that the creation of the working program is ended.
In the teaching point check operation, if the attitude angles (=the rotating angles of the rotational axis 52 and the attitude axis 54) are to be changed, it is necessary to readjust the attitude angles at the teaching points, and the attitude angles are corrected according to the above procedure.
As mentioned above, in the working head of the three-dimensional laser working machine having the head structure that the working points do not change when the rotational axis and the attitude axis are rotated, when the attitude axis is rotated at the time of teaching, the orthogonal state is broken. For this reason, the operator rotates the rotational axis according to the movement of the attitude axis so as to obtain the orthogonal state. However, with this, since the orthogonal state should be made for each of the teaching points, as a number of the teaching points increases, the teaching takes longer time. Furthermore, if the attitude direction is to be corrected, then there arises a problem that the rotating angles of the rotational axis and the attitude axis should be corrected.
It is an object of the present invention to provide a control apparatus for a three-dimensional laser working machine which is capable of making teaching which maintains an orthogonal state of a laser nozzle with respect to a working surface efficiently and fast in a three-dimensional laser working machine having a head structure that working points do not change when a rotational axis and an attitude axis are rotated.
The control apparatus according to the present invention controls a three-dimensional laser working machine. The three-dimensional laser working machine includes a head structure that working points do not change when a rotational axis and an attitude axis are rotated. The control apparatus decides a tip position and an attitude of a nozzle of the head structure and carries out working based on the decided tip position. This control apparatus comprises a unit which calculates a nozzle direction vector from current angles of the rotational axis and the attitude axis, a unit which calculates an angle where the attitude axis changes for constant time and calculating an angle through which the rotational axis is rotated so that X and Y directions of the nozzle direction vector are kept constant according to an angle change amount of the attitude axis, and a unit which controls the rotation of the rotational axis by the calculated angle. Therefore, the rotational axis can be rotated by the angle which is calculated so that the X and Y directions of the nozzle direction vector are kept constant according to a constant time angle change amount of the attitude axis, and the X and Y directions of the nozzle direction vector can be kept constant.
In the above-mentioned control apparatus, when teaching new teaching point accompanying the rotation of the attitude axis from a teaching point of an orthogonal state, the rotation of the rotational axis is controlled according to the change amount of the attitude axis so that the orthogonal state with respect to a workpiece is obtained. Therefore, the rotational axis can be rotated by the angle which is calculated so that the X and Y directions of the nozzle direction vector are kept constant according to a constant time angle change amount of the attitude axis, and the X and Y directions of the nozzle direction vector can be kept constantly in a direction which is orthogonal to the workpiece.
In the above-mentioned control apparatus, when the attitude axis is rotated in order to correct an attitude direction with respect to the teaching point once created, the rotation of the rotational axis is controlled so that the orthogonal state is obtained with respect to the workpiece according to the change amount of the attitude axis. Therefore, also when the attitude axis is rotated from the orthogonal state at the time of correcting the teaching, the rotational axis can be rotated so as to be kept orthogonal to a working workpiece according to the constant time angle change amount of the attitude axis.
In the above-mentioned control apparatus, constant movement of the nozzle direction vector can be switched between valid and invalid, and when movement instructions such as jog and fast-forward of the attitude axis are given, the rotation of the rotational axis is controlled by the calculated angle so that X and Y directions of the nozzle direction vector are kept constant according to the change amount of the attitude axis. Therefore, constant movement of the nozzle direction vector can be switched between valid and invalid, and the switching between valid and invalid is always possible during the teaching operation, the operation of the control apparatus and the like. Further, when movement instructions such as jog and fast-forward are given to the attitude axis, since the rotational axis is rotated by the angle which is calculated so that the X and Y directions of the nozzle direction vector are kept constant according to the constant time angle change amount of the attitude axis, the operation for obtaining the orthogonal state can be omitted.